^what yhwx said. The constitution (as far as I can tell, I’m certainly no legal expert) is essentially saying, “the right to self protection, coming from the people specifically, is important.”
The idea of popular sovereignty–that people are at the top of the governmental pyramid, is basically the foundational idea of the constitution. The idea that people can take care of themselves and not need a nanny state. Most of the founders would probably be disappointed by our ginormous military and bloated central government (Hamilton being an exceptions)